The present invention relates to a lever device which is particularly usable for sports footgear and in particular for ski boots.
Several types of lever used in ski boots are currently known; for this purpose this same Assignee has filed, on Jul. 17, 1975, an Italian patent, no. 1039897, disclosing a lever constituted by an arm which is pivoted, at one end, by means of an adapted pivot, to a pair of shoulders which are rigidly associated with a flap of the boot, said arm having a toothed region for interacting with the end of a hook which is associable, at its other end, with the other flap of the boot to be closed.
Said known lever requires a surface finish of good aesthetic quality, since it is in view on the boot; this therefore requires the use of materials, such as aluminum or plastics, which have an appreciable aesthetic appearance for the skier but do not, at the same time, have the high strength characteristics required to withstand the stresses and impacts to which they are subjected during sports practice.
In any case, the protrusion of the levers with respect to the lateral surface of the boot does not give said boot a neat aesthetic appearance, and said levers are subject, in case of impact with the snow, to accidental openings or breakages.
As a partial solution to this disadvantage, this same Applicant has filed, on Jan. 21, 1976, an Italian patent, granted as No. 1054289, disclosing a closure assembly for ski boots which, despite using a simplified structure, has been found to be difficult to close, due to the small action surface for the hand, on which the effort must then be exerted.
An Italian patent for utility model, no. 185645 filed on Jan. 20, 1981, also discloses a lever closure system, in particular for motorcycle boots, wherein the arm of the lever, which is still pivoted at one end at an adapted support which is rigidly associated with a flap, is inserted within adapted slots defined on another flap to be closed.
Even this solution, despite having a small number of components, has some disadvantages, such as the direct interaction of the lever arm with the flap to be closed, which entails breakages or deformations due to the different strength of the materials which are in contact with one another.
A French patent, published as No. 2432280 and filed on Aug. 3, 1978, discloses a closure device which is again composed of a U-shaped lever arm and having wings pivoted, at their ends, at an adapted support which is rigidly associated with a flap, a pivot being interposed between said wings and interacting with an adapted rack defined in, and protruding from, the other flap to be joined.
This solution has disadvantages, since the engagement between the lever arm and the rack is not always reliable, because the rack must necessarily be made of plastic material together with the flap of the boot and is thus made of a material which does not withstand the high stresses imparted while skiing.
Among the various described situations, the same Applicant of said French patent in fact provides the use of a single lever arm which has a toothed region which interacts with an adapted pivot which is transversely associated with the wings of a U-shaped bar which is pivoted in a cantilever manner to the other flap to be joined.
Even this solution, therefore, has the above described disadvantages; in addition there is a difficult closure operation for the skier, who must in practice rotate the lever arm through 180.degree..
As a partial solution to this disadvantage, this same Applicant filed, on Sep. 8, 1980, an Italian patent application, No. 22716 B/80, related to a closure device, particularly for ski boots, wherein there is a lever arm which is pivoted, at one end, at one of the flaps to be secured; the end of a traction element is articulated to a median portion of said lever element; said traction element is provided, at its opposite end, with a hook-like element which can be engaged in an engagement seat defined at the other flap to be secured; said traction element has means for adjusting its useful length and at least one substantially flexible portion.
Even this solution, however, constructively comprises a large number of components and protrudes outside the contour of the boot; the closure device furthermore extends considerably longitudinally and affects a very large area of the boot.